Sources with knowledge of the deal say it is "very close to completion" and will secure the future of Scoil Niamh and City West Educate Together National School.
It is understood that the department will pay about €5m for the campus, which is located on Fortunestown Lane in west Dublin.
The building was initially part of Mansfield's plans for a boutique golf village at Citywest.
The colourful developer wanted to create a facility where people could shop and play a round of golf at the same location.
However the plans were shelved when the property market collapsed and Mansfield instead attempted to develop an international education campus in 2010.
The businessman wanted to house 750 Saudi students in a live-in English language school.
These plans also foundered, after sparking fears in government circles that they could lead to ghettoisation and problems with integration.
Mansfield's company is now in receivership and the buildings are leased to the department by the receivers.
Now, it has emerged that the Department of Education is in advanced negotiations with the receivers to purchase the site outright.
While a number of figures have been speculated, sources say the department is willing to pay €5m for the site.
This would be seen as a major bargain for the taxpayer.
"Here you have a situation where two schools are benefiting from this site, which for a significant period of time was lying mostly idle," a source explained.
"It is felt that a good deal can be secured with the receivers and, if that happens as planned, it will be a great boost to west Dublin."
The two schools currently share a playground and other facilities, while break times are staggered in order to keep routines separate.
A significant amount of investment has also gone into technology such as interactive whiteboards.
A spokeswoman for Mr Quinn said she could not comment on matters such as acquisitions.
"There are commercial sensitivities involved here, so at this point in time the department cannot make any comment."